AU770203B2

AU770203B2 - Anchoring system for injection molded magnets on a flux ring or motor housing

Info

Publication number: AU770203B2
Application number: AU31198/01A
Authority: AU
Inventors: Hung T. Du; Michael Kunz; Robert J. Marcinkowski; Earl M. Ortt; Brandon Verbrugge
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2000-01-27
Filing date: 2001-01-26
Publication date: 2004-02-19
Anticipated expiration: 2021-01-26
Also published as: CN1298091C; JP2004500797A; GB2359669A; WO2001056134A1; WO2001056134B1; GB0102076D0; CN1310509A; CA2398011A1; DE10103434A1; EP1252702A1; AU3119801A; CH695843A5

Description

1 ANCHOR SYSTEM FOR INJECTION MOLDED MAGNETS ON A FLUX RING OR MOTOR HOUSING BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to power tools and, more particularly, to motors for power tool flux rings with anchors to retain molded magnets on the flux ring.

In motor constructions, the motor magnets must be retained on the housing or separate flux ring within the housing. Ordinarily, these magnets have been glued or adhered to the metallic ring or housing. In adhering the magnets to the metallic surface so that the magnets do not shift during use, various types of adhesives have been used. While some of the adhesives have been satisfactory, some adhesives work better than others. As the adhesives age, it is possible that if the power tool is dropped, that the sudden shock will destroy the bond between the magnet and the housing or ring, enabling the magnet to travel within the motor. When this occurs, the motor ceases to function. Thus, it would be desirable to provide a mechanism to retain the magnets in position on the ring or housing.

The objective of the present invention is provide an improved mechanism for retaining magnets onto a flux ring or motor housing and to a power tool including such improved mechanisms. Due to the advent of molded magnets, it is possible to provide an anchor in the flux ring or housing to retain the molded material on the ring or housing. One such anchoring member is an aperture having a counter-sink on the exterior of the ring or housing. Thus, when the magnet is molded onto the ring, the magnetic material that passes through the ring into the counter-sink forms a solid rivet-shaped fastener. Also, anchors may be stamped out of the ring or housing and project into the interior of the ring to receive the molded magnetic material. The anchors include gussets to reinforce the bend points to enhance the strength of the anchors and help resist deformation during molding. Due to the anchors being unitarily formed or stamped from the ring or housing, an aperture is left in the ring or housing after stamping, which is likewise filled with the molded magnetic material.

In according with a first aspect of the invention, there is provided a flux ring including an annular housing; at least one magnet molded onto said housing; and 2 an anchor on said housing retaining said at least one magnet on said annular housing characterized in that; a bend is in said anchor and said anchor is unitarily formed with said housing and a reinforcement member is positioned at said bend on said anchor for strengthening said anchor. The annular housing may be metal with the anchor projecting radially from the housing. The projecting anchor may have an aperture adjacent to the anchor on the housing. Thus, the magnetic material may mold around the anchor and into the aperture. The anchor may have several different shapes. Preferably, the anchor has a rectangular shape, with one or both ends connected to the housing. Also, the anchor may have an L- or T-shape with one end connected to the housing. Further, the anchor may have a truncated cone shape with an axial aperture through the cone.

In accordance with a second aspect of the invention, a flux ring is provided having an annular housing at least one magnet molded onto said housing; a first anchor on said housing retaining said at least one magnet on said annular housing, said anchor being unitarily formed with said housing; wherein said first anchor includes an aperture, said aperture including a counter-sink portion on an exterior surface of said housing characterized in that, a second is provided on said housing also retaining said at least one magnet on said housing; and a bend of said second anchor having a reinforcing member positioned at said bend for strengthening said second anchor.

The second anchor may have several different shapes. Preferably, the second anchor has a rectangular shape, with one or both ends connected to the housing. Also, the second anchor may have an L- or T-shape with one end connected to the housing. Further, the anchor may have a truncated cone shape 25 with an axial aperture through the cone.

In accordance with a third aspect of the invention, a motor is provided S including: a stator assembly, said stator assembly including a flux ring including: S:an annular housing; 0 30 at least one magnet molded onto said housing; an anchor on said housing retaining said at least one magnet onto said annular housing, said anchor being unitarily formed with said housing and a reinforcement member on said anchor for strengthening said anchor; .:900 an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator.

The annular housing may be made of metal with the anchor projecting radially inward from the housing. The projecting anchor may have an aperture adjacent to the anchor on the housing. Thus, the magnet may mold around the anchor and into the aperture. The anchor may have several different shapes.

Preferably, the anchor has a rectangular shape, with one or both ends connected to the housing. Also, the anchor may have an L- or T-shape with one end connected to the housing. Further, the anchor may have a truncated cone shape with an axial aperture through the cone.

In accordance with a fourth aspect of the present invention, there is provided a motor having a stator assembly, said stator assembly including a flux ring including; an annular housing; at least one magnet molded onto said housing; an anchor on said housing retaining said at least one magnet onto said annular housing; an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator, characterized in that: a bend is in said anchor, said anchor is unitarily formed with said housing, and a reinforcement member is positioned at said bend on said anchor for strengthening said anchor.

~In accordance with a fifth aspect of the invention, a power tool is provided including: 25 a housing; *a motor in said housing, said motor including: a stator assembly, said stator assembly including a flux ring having an annular housing; at least one magnet molded onto said annular housing; an anchor on said housing retaining said at least one magnet onto said annular housing, said anchor being unitarily formed with said annular housing and a reinforcement member being provided on said anchor for strengthening said anchor; an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; brush assemblies associated with said commutator; a power supply; an output member coupled with said motor shaft; and an actuator member electrically coupled between said motor and said power source for energizing and de-energizing said motor which, in turn, rotates said output member when said motor is energized.

The annular housing may be made of metal with the anchor projecting radially inward from the housing. The projecting anchor may have an aperture adjacent to the anchor on the housing. Thus, the magnet molds around the anchor and into the aperture. The anchor may have several different shapes.

In accordance with a sixth aspect of the invention, a power tool is provided having a housing a motor in said housing, said motor including: a stator assembly, said stator assembly including a flux ring having: an annular housing, at least one magnet molded onto said annular housing; an anchor on said t housing retaining said at least one magnet onto said annular housing, an go armature rotatable within said stator assembly; a commutator rotatable with said o •armature and connected to said armature via a shaft; brush assemblies 25 associated with said commutator; a power supply; an output member coupled with said motor shaft; and an actuator member electrically coupled between said S• motor and said power source for energizing and de-energizing said motor which, in turn, rotates said output member when said motor is energized characterized in that: a bend is in said anchor, said anchor is unitarily formed with said annular oooo housing, and a reinforcement member is positioned at said bend on said anchor 0i o: for strengthening said anchor.

In accordance with a seventh aspect of the invention, a motor is provided including an annular housing at least one molded magnet received on said housing; a first anchor on said housing retaining said at least one magnet on said annular housing, said first anchor being unitarily formed with said housing, wherein said first anchor includes an aperture, said aperture including a countersink portion on an exterior of said housing, and a second anchor on said housing; a reinforcement member on said second anchor for strengthening said second anchor; an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator.

According to an eighth aspect, a motor is provided having an annular housing with at least one molded magnet received on said housing, a first anchor on said housing retaining said at least one magnet on said annular housing, said first anchor being unitarily formed with said housing, wherein said first anchor includes an aperture, said aperture including a counter-sink portion on an exterior of said housing, an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator, characterized by a second anchor being provided on said housing, a bend disposed on said second anchor, with a reinforcement member positioned at said bend on said second anchor for strengthening said second anchor.

S 25 Additional preferred objects and advantages and features of the present invention will become apparent from the detailed description of preferred embodiments hereinafter described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS 30 Figure 1 illustrates a cross-section view of a power tool in accordance with a preferred embodiment of the present invention.

Figure 2 illustrates a perspective view of a flux ring in accordance'with a preferred embodiment of the present invention.

Figure 3 is a cross-section view through Figure 2 along line 3-3 thereof.

Figure 4 is a perspective view a further preferred embodiment of a flux ring like that illustrated in Figure 2 with the magnets removed.

Figures 5-9 illustrate perspective views of additional preferred embodiments of flux rings in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turing to Figure 1, a power tool in accordance is illustrated and designated with the reference numeral 10. The power tool 10 is illustrated as a drill; however, any type of power tool such as a screwdriver, sander, rotary tool, clippers, saw or the like which utilize an electric motor may be used with the motor of the present invention. The power tool 10 includes a housing 12 which surrounds a motor 14. An activation member 16 is coupled with the motor 14 as well as with a power source 18. The power source 18 may be a power cord (AC current) or the power tool may have a battery (DC current) as shown. The motor 14 is coupled with an output 20 which may include a transmission 22 and a chuck 24 to retain a tool (not shown) with the drill.

e g ooo **o*o WO 01156134 PCT/US01/02697 -6- The motor 14 includes a stator assembly 30 which includes a housing 32, flux ring 34, and magnets 36 and 38. An armature 40 includes a shaft 42, a rotor 44 with laminations 46 and windings 48, as well as a commutator coupled with the shaft 42. The motor also includes end plates 52 and 54. End plate 52 includes a bearing 56 which balances one end of the shaft 58 which is coupled with a pinion 60 which is part of the power tool output. Brushes 62 and 64 which are associated with the commutator 50. A bearing 70 is also coupled with the end cap to balance rotation of the shaft 42.

Turning to Figure 2, the flux ring 34 is illustrated with magnets 36 and 38. The magnets 36 and 38 are of a molded magnetic material. Preferably, the molded material is an injection molded material. The ring 34 is positioned within a die and the magnetic material is molded onto the flux ring. Also, the housing 32 may be used as the flux ring. Thus, the discussion with respect to the ring 34 may equally apply to the metallic housing 32 of the motor 14.

The flux ring 34 includes anchors 80 to retain the magnets 36 and 38 onto the ring 34. The anchors 80 may be of two types. First, anchor 82 is an aperture formed in the annular housing 34. The aperture 82 has a first portion 84 and a second counter-sink portion 86. The counter-sink portion 86 extends to the exterior 88 of the ring 34. Thus, as seen in the cross-section in Figure 3, as the molded magnetic material is received in the aperture 82, the molded material has a neck 92 and a head 94. The head 94 and neck 92 provide an overall rivet appearance, thus the large head 94 acts to retain the magnet 36, 38 on the ring 34. The ring 34 may be comprised of just a plurality of aperture anchors 82 to retain the magnets on the ring 34.

Additional anchors 96 may be utilized on the ring. Anchors 96 project from the interior surface 98 of the ring 34. Ordinarily, the anchors 96 are stamped or the like into the ring 34 forming an aperture 100 immediately adjacent the projecting anchor 96. Thus, when the molded magnetic material forms around the projecting anchor 96, it likewise goes under the anchor 96 and fills in the aperture 100. This provides a firm securement for the magnet onto the ring 34.

WO 01/56134 PCT/US01/02697 -7- The ring 34 illustrated in Figure 2 is illustrated in Figure 4 without the magnetic material. As can be seen, the projecting anchor 96 has an overall rectangular shape with ends 102 and 104 unitarily formed with the ring 34.

The anchor has bends 106, 108 between the legs 110, 112 and web 114. A reinforcement gusset 116 is positioned at the bends 106, 108. The reinforcement gusset 116 strengthens the anchor during the molding process to maintain its shape. The reinforcement gusset 116 may be a dimple or indent at the bend. Likewise, the aperture anchors 82 are illustrated in Figure 4. Also, aperture anchors 82 could be removed and only radially projecting anchors 96 would be used to retain the magnets on the housing.

The rings 34 are ordinarily formed from a rectangular stamped sheet material. The rectangular shaped sheet metal is stamped to form the apertures 82 or the projecting anchors 96 including the reinforcement gussets 116, or both, depending upon which anchoring system is desired. The flat sheet metal part is then rolled into an annular ring and may have a butt joint 99 (as shown), meshing end 101 (as seen in Figure or the like, forming the ring. The ring is then placed within a die where the magnetic material is injection molded onto the ring. The injection molded material moves through the apertures 82 and around the projecting anchors 96 as illustrated in Figure 3. Then the ring is removed from the die, it is ready for insertion into the motor housing. Likewise, the motor housing itself could be utilized as the ring.

In this case, the ring would not be present and the magnets would be molded directly onto the housing with the housing being formed as described.

Moving to Figures 5-9, additional embodiments of the present invention are illustrated. In Figure 5, the flux ring 34' includes optional aperture anchors 82 like those previously described. Here, the projecting anchors 120 have an overall rectangular shape with one end secured to the ring 34'. The reinforcement gusset 116 is formed at the bend. Also, aperture 122 is immediately adjacent the projecting anchor 120.

Moving specifically to Figure 6; another ring 34" is shown. Here, the ring 34" includes optional aperture anchors 82 like those previously described.

Here, the projecting anchor 130 has an overall L-shape. The projecting L is WO 01/56134 PCTIUS01i02697 -8secured at one end to the ring 34". The reinforcement gusset 116 is formed near the ring 34". The aperture 132 immediately adjacent the projecting Lshaped anchor 130 likewise has an L-shape.

Turning to Figure 7, an additional embodiment is shown. Here, the ring 34"' includes optional aperture anchors 82 like those previously defined, as well as projecting anchors 140. The projecting anchors 140 have an overall rectangular shape and are angled inward directly out of the ring The reinforcement gusset 116 is formed near the ring Also, the aperture 142 is immediately adjacent the projecting anchor 140.

Figure 8 illustrates an additional embodiment of the present invention.

The flux ring includes optional aperture anchors 82 like those previously defined. The projecting anchors 160 have an overall T-shape. The apertures 162 immediately adjacent the T-shaped projecting member 160 likewise have a corresponding T-shape. The reinforcement gusset 116 is formed near the ring Thus, as the magnetic material is molded onto the ring, the Tshaped projection 160 is covered by the magnetic material while the T-shaped aperture 162 receives magnetic material both holding the magnets in place on the ring 34"".

Turning to Figure 9, an additional embodiment of the flux ring is shown. Here, the flux ring includes optional aperture anchors 82 like those previously described. The projecting anchors 150 have a truncated cone shape. The truncated cones 150 include axial apertures 152. The axial apertures enable the molded magnetic material to move into the cone 154 formed on the exterior surface of the flux ring 34"".

While the above detailed description describes the preferred embodiment of the present invention, the invention is susceptible to modification, variation, and alteration without deviating from the scope and fair meaning of the subjoined claims.

Claims

1. A flux ring, including an annular housing; at least one magnet molded onto said housing; and an anchor on said housing retaining said at least one magnet on said annular housing characterized in that; a bend is in said anchor and said anchor is unitarily formed with said housing and a reinforcement member is positioned at said bend on said anchor for strengthening said anchor.

2. The flux ring according to claim 1, wherein said annular housing is metal.

3. The flux ring according to claim 1 or claim 2, wherein said anchor projects radially from said housing.

4. The flux ring according to claim 1 or claim 2, wherein said anchor is formed from said housing and provides an aperture adjacent said anchor. The flux ring according to claim 4, wherein said magnet molds around said anchor and into said aperture.

6. The flux ring according to claim 1 or claim 2, wherein said anchor has an overall rectangular shape with two ends connected to said housing with reinforcement members at bends.

7. The flux ring according to claim 1 or claim 2, wherein said anchor has an :00:00 overall rectangular shape with one end connected to said housing. S• 8. The flux ring according to claim 1 or claim 2, wherein said anchor has an o o 20 overall L-shape with one end connected to said housing.

9. The flux ring according to claim 1 or claim 2, wherein said anchor has an overall T-shape with one end connected to said housing. ooo* o o 00* The flux ring according to any one of claims 6 to 9, wherein a said bend with said reinforcement member is located between said anchor and said housing.

11. A flux ring having an annular housing at least one magnet molded onto said housing; a first anchor on said housing retaining said at least one magnet on said annular housing, said anchor being unitarily formed with said housing; wherein said first anchor includes an aperture, said aperture including a counter- sink portion on an exterior surface of said housing characterized in that, a second is provided on said housing also retaining said at least one magnet on said housing; and a bend of said second anchor having a reinforcing member positioned at said bend for strengthening said second anchor.

12. The flux ring according to claim 11, wherein said second anchor is a portion of said housing having an aperture adjacent to said second anchor.

13. The flux ring according to claim 11 or claim 12, wherein one end of said second anchor is connected to said housing.

14. The flux ring according to claim 11 or claim 12, wherein said second anchor has an overall L-shape with one end connected to said housing. The flux ring according to claim 11 or claim 12, wherein said second 0 0 anchor has an overall T-shape with one end connected to said housing. 0 0

16. The flux ring according to any one of claims 11 to 15, wherein said first anchor has a truncated cone shape.

17. The flux ring according to claim 16, wherein said truncated cone shape of 0° said first anchor has an axial aperture. 0 0000

18. A motor including: a stator assembly, said stator assembly including a flux ring including: 11 an annular housing; at least one magnet molded onto said housing; an anchor on said housing retaining said at least one magnet onto said annular housing, said anchor being unitarily formed with said housing and a reinforcement member on said anchor for strengthening said anchor; an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator.

19. The motor according to claim 18, wherein said annular housing is metal. The motor according to claim 18, wherein said anchor includes a bend, said reinforcement member being positioned at said bend.

21. A motor having a stator assembly, said stator assembly including a flux ring including; an annular housing; at least one magnet molded onto said housing; an anchor on said housing retaining said at least one magnet onto said o annular housing; an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator, characterized in that: a bend .°oooi is in said anchor, said anchor is unitarily formed with said housing, and a S 20 reinforcement member is positioned at said bend on said anchor for strengthening said anchor.

22. The motor according to any one of claims 18 to 21, wherein said anchor is a portion of said housing and has an aperture adjacent said anchor. 12

23. The motor according to claim 22, wherein said anchor has an overall rectangular shape with two ends connected to said housing.

24. The motor according to claim 22, wherein one end of said anchor is connected to said housing.

25. The motor according to claim 22, wherein said anchor has an overall L- shape with one end connected to said housing.

26. The motor according to claim 22, wherein said anchor has an overall T- shape with one end connected to said housing.

27. A power tool including: a housing; a motor in said housing, said motor including: a stator assembly, said stator assembly including a flux ring having an annular housing; at least one magnet molded onto said annular housing; 15 an anchor on said housing retaining said at least one magnet onto said annular housing, said anchor being unitarily formed with said annular housing and a reinforcement member being provided on said anchor for 0 strengthening said anchor; :..009 .°p an armature rotatable within said stator assembly; S 20 a commutator rotatable with said armature and connected to said armature p via a shaft; i brush assemblies associated with said commutator; 13 a power supply; an output member coupled with said motor shaft; and an actuator member electrically coupled between said motor and said power source for energizing and de-energizing said motor which, in turn, rotates said output member when said motor is energized.

28. The power tool according to claim 27, wherein said annular housing is metal.

29. The power tool according to claim 27, wherein said anchor includes a bend and said reinforcement member is positioned at said bend.

30. A power tool having a housing a motor in said housing, said motor including: a stator assembly, said stator assembly including a flux ring having: an annular housing, at least one magnet molded onto said annular housing; an anchor on said housing retaining said at least one magnet onto said annular housing, an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; brush assemblies associated with said commutator; a power supply; an output member coupled with said motor shaft; and an actuator member electrically coupled between said motor and said power source for energizing and de-energizing said motor which, in turn, rotates said output member when said motor is energized characterized in that: a bend is in said anchor, said anchor is unitarily formed with said annular housing, and a reinforcement member is positioned at said bend on said anchor for strengthening said anchor. S. 31. The power tool according to claim 30, wherein said anchor is a portion of said annular housing and has an aperture adjacent said anchor. 25 32. The power tool according to claim 30, wherein said anchor has an overall rectangular shape with two ends connected to said annular housing. 14

33. The power tool according to claim 32, wherein a said bend with an associated said reinforcement member is provided between each said end of the anchor and an adjacent region of said housing.

34. The power tool according to claim 30, wherein one end of said anchor is connected to said annular housing. The power tool according to claim 30, wherein said anchor has an overall L-shape with one end of said anchor being connected to said annular housing.

36. The power tool according to claim 30, wherein said anchor has an overall T-shape with one end of said anchor being connected to said annular housing.

37. A motor including: an annular housing; at least one molded magnet received on said housing; a first anchor on said housing retaining said at least one magnet on said annular housing, said first anchor being unitarily formed with said housing, wherein said first anchor includes an aperture, said aperture including a counter-sink portion on an exterior of said housing, and a second anchor on said housing; a reinforcement member on said second anchor for strengthening said second anchor; an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator.

38. The motor according to claim 37, wherein said molded magnet enters said aperture forming a rivet-shaped member.

39. The motor according to claim 37, wherein said second anchor includes a bend and said reinforcing member is positioned at said bend.

40. A motor having an annular housing with at least one molded magnet received on said housing, a first anchor on said housing retaining said at least one magnet on said annular housing, said first anchor being unitarily formed with said housing, wherein said first anchor includes an aperture, said aperture including a counter-sink portion on an exterior of said housing, an armature rotatable within said stator assembly; a commutator rotatable with said armature and connected to said armature via a shaft; and brush assemblies associated with said commutator, characterized by a second anchor being provided on said housing, a bend disposed on said second anchor, with a reinforcement member positioned at said bend on said second anchor for strengthening said second anchor.

41. The power tool according to claim 40, wherein said molded magnet enters said aperture of said first anchor forming a rivet-shaped member.

42. A flux ring according to claim 1 substantially as described herein with 0 0. referenced to accompanying drawings. 0 0 S"DATED this 10th day of December 2003 go.o• S"BLACK& DECKER INC WATERMARK PATENT TRADE MARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 g AUSTRALIA SSKP/RW *ooo